Best 'Fast Food" burger made IMHO.
However... if you expand beyond 'fast food' and include some of the small Mom & Pops burger places, or even non-Mom&Pop but local and 'homemade' THEN....
In & Out would rate, again IMHO, WAY down the line... still very very good but no... not as good as many of the Mom & Pop burgers I've had. Should note: I've had more than a few 'bad' Mom & Pop burgers as well.
I'm not a big fast food burger patron to begin with but I've had most of them over the years. To me I can't even imagine how anyone could place Burger King, McD's, Wendy's, Carls Jr., Jack-In-the-Box, over In & Out... that does not compute to me.